When building ASDF modules with the previous cl-asdf port version,
sometimes the build would fail because of "missing" packages that
weren't actually missing (this only happened in ports that aren't
committed yet).
Rewrite the FASL placement code using the asdf-binary-locations
extension, which is already included in the cl-asdf port but needs
to be installed from ports when building for SBCL (which has its
own ASDF code). The binary-locations code generates paths unsuitable
for PLISTs, therefore it has been overridden with
lisp-specific-fasl-subdir.
Because of the new code, PLIST generation for cl-*-sbcl and cl-*-clisp
ports is now entirely automated.
All dependent cl-* ports are upgraded (obsolete code removed,
PORTREVISION bumped).

Remove redundant code and variables from the cl-* ports.
Introduce bsd.cl-asdf.mk to automate the compilation and installation
of Common Lisp libraries using the ASDF framework.
Currently it supports building FASL files on SBCL and CLISP, to
support the ports that already exist in the ports tree.
This should help bringing in more cl-* ports from the ASDF repository
without excessive code duplication.

For ports maintained by ports@FreeBSD.org, remove names and/or
e-mail addresses from the pkg-descr file that could reasonably
be mistaken for maintainer contact information in order to avoid
confusion on the part of users looking for support. As a pleasant
side effect this also avoids confusion and/or frustration for people
who are no longer maintaining those ports.